An open cylindrical tank whose base is a circle is to be constructed of metal sheet so as to contain a volume of `pi a^3 cu.cm` of water.Find the dimensions so that the quantity of metal sheet required is a minimum.
A. Radius=2a cm, Height =2a cm
B. Radius =2a cm, Height=a cm
C. Radius =a cm, Height =a cm
D. Radius = acm, Height = 2a cm
